.: Research

Star Formation and Metallicity History of Star-forming Galaxies

Observing the star formation rate since the earliest times in the universe is crucial to understanding galaxy formation and evolution. Current studies into the cosmic star formation history are hindered by significant discrepancies between star formation rate density estimates at different wavelengths. Metallicity plays a key role in these discrepancies. Metallicity effects on the commonly use star formation indicator [OII] can mimic or hide evolution in star formation as a function of redshift. Theory suggests that metallicity changes less rapidly than SFR as a function of redshift, but there is no solid observational foundation for the cosmic metallicity history of star-forming galaxies. My research combines large local samples, deep field intermediate galaxies, and high-redshift galaxies to gain a simultaneous understanding of the metallicity and star formation in galaxies.

Click here to read a press release, or click here to read a short article about this research.

Theoretical starburst & HII region modelling

Large spectroscopic surveys have provided unparallelled insight into galaxy evolution. One of the major developments in this field was the characterization of the star formation history of the universe. These studies rely on optical emission-lines, UV continuum, radio, or infrared luminosities to derive star formation rates. I combine state-of-the-art stellar population synthesis and photoionization models to derive consistent, reliable spectral emission-line diagnostics for intrinsic galaxy properties that influence star formation rate estimates. These intrinsic properties include ionization state, metallicity, star-formation properties, and contribution from an Active Galactic Nucleus.

Recently, Claus Leitherer and I merged the Starburst99 population synthesis and Mappings photoionization codes into one interactive web interface. We anticipate that this interface will aid in interpreting spectra from the UV to the far-infrared, and facilitate the development of new diagnostics.

My other research areas include:

The link between low metallicity galaxies and gamma-ray burst hosts

Metallicity as a smoking gun for large gas flows in merging galaxies

Luminous infrared galaxies

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